The present invention relates to magnetic devices, such as transformers and inductors, that can be assembled using automated equipment, and surface mounted as other electronic components on circuit cards.
The magnetic components used in power technology do not lend themselves to automated assembly and are therefore expensive to fabricate. Power transformers and output inductors are massive devices which require multiple manual assembly operations.
Power processors have been evolving from large, bulky, central power supplies toward modular, low profile, distributed power supplies. While memory, digital processor, and I/O pages are assembled using automated handling procedures, the power supply components have unique shapes that do not conform to automated handling equipment. The magnetic components of the power supply are particularly troublesome in this regard. Standard magnetic fabrication techniques are better suited for devices that have a cubic or high profile outlines. Automatic handling equipment requires low profile components typically less than 0.2 inches.
One way of reducing the profile of conventional transformers is to use planar construction techniques. The planar transformer has the winding etched on a printed circuit board and sandwiched between core pieces. Standard planar transformers are available with profiles as low as 0.325 inch. There is an optimum profile for the maximum power density of planar pot core transformers. At profiles below the optimum, the power density decreases rapidly, due to the thickness of the circuit board material, making it difficult to fabricate a planar transformer having a thickness less than 0.1 inches.
It is an object of the present invention to provide a low profile magnetic device that is compatible with automated assembly equipment.
It is another object of the present invention to provide magnetic devices that can be placed on circuit cards and surface mounted the same way as electronic components.
It is a further object of the present invention to provide a reconfigurable and expandable transformer that is compatible with automated assembly equipment.